1. Field of the Invention
The present invention relates to a disc drive such as a CD player, and more particularly to a disc clamp mechanism capable of thinning a disc drive.
2. Description of the Related Art
An example of a conventional disc clamp mechanism for a CD player is shown in FIGS. 7A to 9B. As shown in FIGS. 7A and 7B, a disc motor 3 is fixedly mounted on a main chassis (not shown), and a turntable 4 is fixedly connected to a rotary shaft of the disc motor 3. A clamper holder 2 fixed to a clamper holding chassis 1 holds a clamper 8 over the turntable 4 when a disc 7 is unclamped, as shown in FIG. 7B.
A lift mechanism for the clamper holding chassis 1 is shown in FIG. 8 and FIGS. 9A and 9B. Shafts 1a, 1a . . . mounted upright on side walls of the clamper holding chassis 1 are inserted into cam grooves 5a, 5a, . . . of sliders 5 and 6.
The sliders 5 and 6 are driven back and forth relative to the main chassis by an unrepresented drive mechanism. As the sliders 5 and 6 move, the clamper holding chassis 1 is raised and lowered. The shafts 1a, 1a, . . . are also inserted into vertical grooves (not shown) of the main chassis.
In the disc unclamp state shown in FIG. 7B, the clamper holding chassis 1 is at a raised position. The disc 7 is transported by an unrepresented transport mechanism to a position over the turntable 4 via a space between the turntable 4 and clamper 8. Thereafter, as the clamper holding chassis 1 is lowered, the clamper holder 2 places the clamper 8 on the turntable 4 and becomes spaced apart from the clamper 8.
The clamper 8 is then attracted by a magnetic force of the turntable 4 to squeeze the disc 7 between the clamper 8 and turntable 4. This state is a clamp state of the disc 7 as shown in FIG. 7A. The clamped disc 7 is rotated by the disc motor 3, and an unrepresented optical pickup element is fed along a disc radial direction to reproduce data recording in the disc 7.
Unclamping the disc 7 is conducted by raising the clamper holding chassis 1 from the position shown in FIG. 7A. The clamper holder 2 is made of a thin plate in order to prevent a contact with the disc 7 and turntable 4 while the disc 7 is clamped.
In the conventional disc clamp mechanism described above, the clamper 8 greatly lowers toward the turntable 4 from the bottom surface of the clamper holding chassis 1 in the disc unclamp state. It is therefore difficult to provide a large space between the clamper 8 and turntable 4. From this reason, the disc 7 may contact the clamper 8 or turntable 4 while it is transported and the disc 7 may be damaged.
If a lift stroke of the clamper holding chassis 1 is made large, a large space can be formed between the clamper 8 and turntable 4. However in this case, a height of the apparatus becomes large.
The applicant of this application filed JP Patent Application No. 9-273540 which proposes a disc clamp mechanism for a disc apparatus capable of solving the above problems and providing a large space between a clamper and a turntable in a disc unclamp state even if the apparatus is made compact. This disc clamp mechanism for a disc apparatus is shown in FIGS. 10A to 14. The operation principle of this disc clamp mechanism for a disc apparatus will be described. In FIGS. 10A to 14, elements having similar functions to those of the conventional mechanism described with reference to FIGS. 7A to 9B are represented by using identical reference numerals, and the detailed description thereof is omitted.
In this example, a clamper holder 2 is made of a plate spring. A contact portion of the clamper holder 2 with a clamper 8 is deformed upward in a disc unclamp state. In this state, the bottom surface of the clamper 8 held by the clamper holder 2 is raised higher than the bottom surface of a clamper holding chassis 1. FIG. 10B shows a clamp state of a disc 7.
With reference to FIGS. 11 to 14, the way the clamper holder 2 is deformed will be described. FIG. 12E shows the shape of the clamper holder 2. The clamper holder 2 has a projection 2a at its distal end portion. In a natural state not applied with a force, the clamper holder 2 is bent two steps so that the surface of the projection 2a is lower than its base end portion.
The fixed end portion of the clamper holder 2 is fixed to a lever 9 shown in FIG. 11. The lever 9 is rotatively fitted in the clamper holding chassis 1 and is rotated by a slider 5 as shown in FIGS. 13 and 14.
More specifically, a shaft 5b mounted upright on the slider 5 is inserted in a vertical groove (not visible in FIGS. 13 and 14) formed in a bent portion of the lever 9. As shown in FIG. 13, as the slider 5 makes the clamper holding chassis 1 rise, the lever 9 is rotated in the clockwise direction as viewed from a higher position, whereas as shown in FIG. 14, as the slider 5 makes the clamper holding chassis 1 lower, the lever 9 is rotated in the counter-clockwise direction as viewed from a higher position.
While the lever 9 is rotated as the clamper holding chassis 1 is raised or lowered, a relative motion of the lever 9 and clamper holding chassis 1 deforms the projection 2a of the clamper holder 2 fixed to the lever 9.
FIGS. 12A to 12D show a deformation of the projection 2a of the clamper holder 2. FIGS. 12A to 12D are drawn assuming that a weight of the clamper 8 is not applied to the clamper holder 2. The clamper holding chassis 1 is raised in the sequential order of FIGS. 12A to 12D. As shown, the projection 2a of the clamper holder 2 deforms along the motion direction of the clamper holding chassis 1.
Accordingly, as shown in FIG. 10A, the bottom surface of the clamper 8 becomes higher than the bottom surface of the clamper holding chassis 1 in the unclamp state of a disc 7. It is therefore possible to form a large space between the clamper 8 and a turntable 4 and prevent the disc 7 from contacting the clamper 8 or turntable 4 and being damaged while the disc 7 is transported. Furthermore, a stroke of the clamper holding chassis 1 necessary for reserving the space becomes small so that the disc apparatus can be made compact.
The disc clamp mechanism proposed in JP Patent Application No.9-27354 described above has a sufficient space between the turntable 4 and clamper 8 when a disc is loaded or unloaded. However, as shown in FIGS. 10B and 10C, since the clamper holder 2 is positioned between the clamper 8 and disc 7 in the disc clamp state, a gap A (shown in FIG. 10C) between the clamper holder 2 and clamper 8 and a gap B (shown in FIG. 10C) between the clamper holder 2 and disc 7 are difficult to be made sufficient during the disc rotation.
Therefore, abnormal friction sounds between the clamper holder 2 and clamper 8 or disc damages to be caused by a contact between the clamper holder 2 and disc 7 may occur depending upon variations in sizes of components, variations in thicknesses of discs, rotation plane fluctuations and the like.
The invention has been made in view of the above problems. It is an object of the present invention to provide a disc clamp mechanism for a disc apparatus capable of providing a large space between a clamper and a turntable in a disc unclamp state even if the apparatus is made compact, and capable of preventing a contact between the clamper holder and clamper and between the clamper holder and disc while the disc is rotated.
According to one aspect of the present invention, there is provided a disc clamp mechanism for a disc apparatus for clamping or unclamping a disc by moving a clamper holding chassis near to or remote from a turntable, the clamper holding chassis holding a clamper with a clamper holder, wherein: a lever is rotatively supported by the clamper holding chassis and moved in cooperation with a motion of the clamper holding chassis; and a contact portion of the clamper holder with the clamper is displaced in a motion direction of the clamper holding chassis and a clamper radial direction relative to the clamper holding chassis, in cooperation with a motion of the lever relative to the clamper holding chassis.
In the disc clamp mechanism for a disc apparatus, the clamper holder may be made of a plate spring.
In the disc clamp mechanism for a disc apparatus, the contact portion of the clamper holder is moved in a direction away from the disc and in a direction away from the clamper when the disc is clamped.